1. Field of the Invention
The present invention relates to a starter, for example, mounted on a vehicle.
This application claims benefit of Japanese Patent Application No. 2011-047558 filed on Mar. 4, 2011 which is hereby incorporated by reference.
2. Description of Related Art
A starter used for starting a vehicle is known which includes in a housing, a motor section (a motor), an electromagnetic switch opening and closing a main contact disposed at a motor circuit, a pinion shaft which rotates driven by the motor section, a pinion gear integrally supported with a clutch by the pinion shaft, an intermediate shaft arranged parallel to the pinion shaft, an intermediate gear supported on the intermediate shaft, and a retainer connecting the pinion gear and the intermediate gear (a member that retains the pinion gear and the intermediate gear by connecting both each other). Thus, the starter includes a configuration in which the intermediate gear moves integrally with the pinion gear through the retainer and thereby meshes with a ring gear of an engine.
The electromagnetic switch forms an electromagnet by electrical connection to an electromagnetic coil. The electromagnetic switch has a solenoid driving (attracting) a plunger with an attraction force of the electromagnet, and a contact cover fixed at the solenoid and made of resin. The main contact is arranged inside the contact cover. In addition, the clutch is connected to the plunger of the electromagnetic switch through a shift lever. Thus, the movement of the plunger is transmitted through the shift lever and thereby the clutch moves on the pinion shaft in an axial direction with the action of a helical spline.
Under such a configuration, when the electromagnetic switch is electrically connected to the electromagnetic coil to form the electromagnet, the plunger is attracted and moved to the electromagnet. When the movement of the plunger is transmitted to the clutch through the shift lever, the pinion gear moves integrally with the clutch on the pinion shaft in a direction opposite to the motor section, and at the same time, the intermediate gear connected to the pinion gear by the retainer moves in a meshed state with the pinion gear.
In addition, when the main contact is closed by the electromagnetic switch, the power is supplied from an in-vehicle battery to the motor section and thereby rotational force is generated at an armature. Thus, the rotational force is transmitted to the pinion shaft through a reduction gear. The rotation of the pinion shaft is transmitted to the pinion gear through the clutch and furthermore, transmitted to the intermediate gear meshed with the pinion gear. Thus, a driving torque of the motor section is transmitted from the pinion gear to the ring gear through the intermediate gear and thereby cranking the engine (for example, see Japanese Unexamined Patent Application, First Publication No. 2007-132296).
However, in the related art described above, when an excessive load is applied to the starter, for example, during a collision at the front of the vehicle, the housing may be deformed. In this case, when the deformed portion of the housing is, for example, a portion corresponding to the electromagnetic switch or the shift lever, the electromagnetic switch, the shift lever or the like may be deformed according to the deformation of the housing. When the electromagnetic switch, the shift lever or the like is deformed, the main contact may be closed. In this case, unnecessary power may be supplied to the motor section.
The invention has been made in light of such circumstances, and has an object of providing a starter which can reliably prevent supplying an unnecessary power to a motor section even though an excessive load is applied.